CLONAL EXPANSIONS OF V-DELTA-1(-DELTA-2(+) CELLS INCREASE WITH AGE AND LIMIT THE REPERTOIRE OF HUMAN GAMMA-DELTA T-CELLS() AND V)

We have investigated the complexity of the human gamma delta T cell re pertoire by means of a VJ heteroduplex analysis method. cDNA obtained from peripheral blood mononuclear cells was amplified with V delta 1-C delta or V delta 2-C delta primers. The product was denatured and ren atured to allow random reannealing of the strands and the heteroduplex es carrying mismatched junctional sequences were separated from the ho moduplexes on polyacrylamide gels. Whenever one or more T cell clones were expanded to over 10% of the polyclonal background, discrete bands of homo- and heteroduplex appeared. This method was applied to the an alysis of the peripheral gamma delta compartment from healthy donors a nd rheumatoid arthritis patients of different ages. While samples from young individuals showed a polyclonal pattern, a clear tendency towar ds oligoclonality appeared with increasing age, both in normal individ uals and rheumatoid arthritis patients. We also show that the VJ junct ional sequence derived from the heteroduplex fragments can be successf ully used to isolate and characterize the corresponding T cell clones in vitro, even after a period of 1 year. In conclusion, our findings i ndicate that the complexity of the gamma delta T cell repertoire decre ases with age as a consequence of the expansion of a few T cell clones .